1. Field of the Invention
The invention relates to imaging of body organs and tissues. The invention also relates to systems and methods for classifying tissue types.
2. General Background and State of the Art
Ultrasound has been a popular medical imaging technique for many years. Ultrasonic imaging typically involves measurements of a single acoustic parameter by transmitting an acoustic signal into a tissue and analyzing the response. For example, reflectivity coefficients may be used to generate reflection images, and attenuation or time-of-flight data may be used to generate transmission images. Sinogram data can be derived from multiple measurements of the acoustic parameter, from which a single-parameter image can be subsequently generated. Such images might be used to visualize a developing baby or circulation of blood, for example.
However, these single-parameter imaging methods are not always sufficient for classifying various types of tissue within an imaged tissue portion. One reason is that such methods typically involve measuring the acoustic parameter, such as attenuation, from peak amplitude values or from total energy of the received. Because ultrasonic signals commonly experience errors of up to 10%, the captured image data often is not sufficiently accurate to classify tissue types accurately. Even time of flight-based imaging has its tissue type classification potential hindered due to frequency-dependent dispersion effects of ultrasonic propagation in tissues that comprise nonlinear inhomogenous propagation medium. There currently are not known methods for accurately classifying portions of a tissue sample according to tissue type through enhancement of a single acoustic parameter of the tissue sample.
The present invention helps solve these and other problems by providing methods and systems for classifying different tissue types through enhancement of a single acoustic trait by extracting multiple aspects therefrom.
In one embodiment, a method for classifying a tissue that is irradiated with an ultrasonic signal includes receiving an interaction signal resulting from the interaction between the ultrasonic signal and at least one portion of the tissue, extracting at least first and second characterizing data from an initial portion of the interaction signal characterizing at least a first and second aspect, respectively, of the initial portion of the interaction signal, the first aspect being different from the second aspect, calculating first and second identification data as a function of the first and second characterizing data, respectively, and matching the first and second identification data to a tissue type by consulting a database containing information correlating identification data associated with at least the first and second aspects to tissue type.
In another embodiment, a method for classifying a tissue that is irradiated with an ultrasonic signal includes receiving an interaction signal resulting from the interaction between the ultrasonic signal and at least one portion of the tissue; performing a Fourier transform on an initial portion of the interaction signal, and calculating a characteristic of the tissue portion as a function of the Fourier transform of the initial portion of the interaction signal.
In a further embodiment, a system for performing a method of classifying a tissue that is irradiated with an ultrasonic signal includes a transmission element for irradiating a portion of the tissue with an ultrasonic signal, a receiver element for subsequently receiving an interaction signal resulting from an interaction between the radiated ultrasonic signal and the tissue portion, and a data storage device for storing a database containing information correlating identification data of first and second tissue aspects with tissue type. The system further includes a processor operatively connected to the receiver element and configured to process the interaction signal and extract at least first and second characterizing data therefrom, the characterizing data characterizing at least a first and second aspect, respectively, of an initial portion of the interaction signal. The processor is further configured to calculate identification data as a function of the characterizing data, the identification data representative of at least first and second aspects of the tissue portion. The processor is operatively connected to the data storage device, and further configured to match the identification data to a tissue type by consulting the tissue type database.
In yet another embodiment, a system for classifying a tissue that is irradiated with an ultrasonic signal includes a transmission element for irradiating a portion of the tissue with an ultrasonic signal and a receiver element for subsequently receiving an interaction signal resulting from an interaction between the radiated ultrasonic signal and the tissue portion. A processor is operatively connected to the receiver element and configured to process the interaction signal and identify the initial portion thereof, perform a Fourier transform on the initial portion of the interaction signal, and calculate a characteristic of the tissue portion as a function of the Fourier transform.
The foregoing and other objects, features, and advantages of the present invention will become apparent from a reading of the following detailed description of exemplary embodiments thereof, in conjunction with the accompanying drawing Figures.